BOOKS AND CURRENT LITERATURE 



Vegetation of the Transcaspian Lowlands. — The desert region to 

 the east of the Caspian Sea, though never thoroughly worked botani- 

 cally, was explored by Ove Paulsen in 1898-99, on the Second Danish 

 Pamir Expedition, and he has already published various papers on the 

 systematic botany of the region explored. The present volume 1 is 

 largely devoted to the physiognomy of the vegetation of the Trans- 

 caspian Desert; it is well illustrated, and what with its clear descriptions, 

 the discussion of formations and growth forms, the accounts of vegeta- 

 tion from selected localities, together with plant lists and statistics, it is 

 possible for one accustomed to such studies to form a satisfactory and 

 relatively complete picture of the distribution and characteristic features 

 of the plant life of the area thus far under investigation. 



Omitting further reference to the numerous, often important, details 

 given under the preceding divisions of the work, a brief resume of the clos- 

 ing chapter, with its main conclusions, is all that will now be attempted. 

 Turkestan and Central Asia were covered by the sea during the Cre- 

 taceous and Tertiary periods, and with the emergence of Transcaspia 

 at the beginning of the Quaternary the climate, previously moist and 

 favorable to plant growth, became dry. As a necessary result, the 

 plants of what is now the Transcaspian Desert must die or adapt them- 

 selves to new conditions, and at the same time this region became open 

 to immigration from neighboring countries. Under these circumstances 

 a relatively large number of endemic species developed, but the close 

 floristic relationship between Transcaspia and the surrounding country 

 shows that the former has also received a large precentage of its flora 

 by immigration. Of the 768 Transcaspian species enumerated, the 

 endemic species constitute 22 per cent, the remainder being distributed 

 towards the east, north, and south in such percentages as to indicate 

 that a larger number of immigrants are from the south than from any 

 other direction. Most of the genera containing endemic species have 

 their main distribution in the Mediterranean countries and in Western 

 Asia, an indication that the flora of Transcaspia is closely related to the 

 flora of those countries. 



1 Paulsen, Ove, Studies on the Vegetation of the Transcaspian Lowlands. The 

 Second Danish Pamir Expedition, pp. 279 and map. Copenhagen, 1912. 



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